Reagent mixtures for self-contained temperature-change container assemblies

ABSTRACT

A container assembly heats or cools a product inside an inner container. An outer jacket at least partially surrounds the inner container, with a first internal volume and a second internal volume in the space between the outer jacket and the inner container. A first temperature-change reagent is contained inside the first internal volume, and a second temperature-change reagent is held in the second internal volume, with a reagent separator between the two. Several penetrators are disposed to penetrate the reagent separator to produce openings through the separator and through which the two reagents can mix. Steel wool inside the first internal volume acts as a steam condenser. The outer jacket includes a jacket top ring secured around an upper surface of a standard can, a jacket body secured to the jacket top, and a flexible jacket bottom that carries several spikes molded onto the jacket bottom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 10/756,954, filed Jan. 12, 2004, which is acontinuation-in-part of co-pending U.S. patent application Ser. No.10/613,322, filed Jul. 3, 2003, which applications are herebyincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

The invention relates generally to containers and apparatus for heatingor cooling materials held inside containers. More particularly, theinvention provides a can or a similar container for holding a foodproduct or another material, and a self-contained assembly for heatingor cooling the container and the material within it to a temperatureabove or below the material's storage temperature. In a preferredembodiment, a standard metal can holds a quantity of a food or beverage.A jacket or housing surrounds the can, with reagents for an exothermicor endothermic temperature-change reaction inside the jacket inproximity to the can. Activating the device initiates the reaction toheat or cool the can and its contents.

Devices of this general type are known in the art. Some such devicesinclude a food container in proximity to a reagent storage vessel. Thereagent storage vessel holds a quantity of calcium oxide and a quantityof water, with a barrier between them to keep the two reagentsseparated. The devices include some mechanism for breaching the barrierto allow the calcium oxide and water to mix. When this occurs, theresulting exothermic reaction generates heat that is transferred intothe food container to raise the temperature of a food product inside thecontainer.

The prior art devices suffer from various deficiencies, though. Some ofthe devices are prone to leak either steam or heated reactants from thereagent mixture. These devices can be hazardous in use. Concern over thepossible injuries to users has severely hindered the acceptability ofthese devices in the marketplace. Other devices do not adequatelycontrol the rate of the reaction after its initiation. The reaction mayproceed either too fast or too slow, and too much or too little heat maybe transferred to the food. Other devices are overly complex, anddifficult, expensive, or time-consuming to manufacture, assemble, useand dispose of. For these reasons and others, there has never been anacceptable mass-market, self-heating product until now.

A need exists, therefore, for self-contained temperature-changecontainer assemblies that are improved in comparison with those of theprior art. Such an assembly should be safe and reliable in use, and easyand inexpensive to manufacture. Container assemblies of this type, andmethods for manufacturing in them, are described below in this document.

SUMMARY OF THE DISCLOSURE

The invention is embodied in a self-contained, temperature-changecontainer assembly operable to heat or cool a product packaged inside aninner container inside the assembly. The product may be a food orbeverage, or it may be another type of product.

A preferred embodiment of the assembly includes an outer jacket that atleast partially surrounds the inner container, with a first internalvolume and a second internal volume in the space between the outerjacket and the inner container. A first temperature-change reagent iscontained inside the first internal volume, and a secondtemperature-change reagent is held in the second internal volume, with areagent separator between the two.

The preferred embodiment includes a movable member with severalpenetrators situated to penetrate the reagent separator to produceopenings through the separator and through which the two reagents canmix. Mixing the reagents initiates a chemical reaction—exothermic orendothermic—in order to heat or cool the inner container and a productcontained within it.

In the preferred embodiment, the first temperature-change reagent iscalcium oxide and the second temperature-change reagent is liquid water.Mixing the two results in an exothermic reaction that generates heat toraise the temperature of the product inside the container.

In a particularly preferred embodiment, steel wool is provided insidethe first internal volume. The steel wool, which is an efficient thermalconductor with a large surface area, acts as a steam condenser tocontrol the formation of steam generated by the reaction.

The outer jacket can comprise a jacket top ring secured in place aroundan upper surface of a standard can, a jacket body secured to the jackettop, and a flexible jacket bottom that acts as a movable member andwhich carries several penetrators in the form of spikes molded onto thejacket bottom.

The assembly can be manufactured by fixing a jacket top ring around asealed inner container, fixing a jacket body onto the jacket top ring,filling first and second reagents inside the jacket body with a reagentseparator between them, and then installing a flexible jacket bottomonto the jacket body with penetrators or spikes provided opposite thereagent separator.

Preferred embodiments will use standard size cans so that a food orbeverage manufacturer or canner may designate some units of its outputfor sale to consumers as usual, and other units for inclusion intemperature-change container assemblies according to the invention, withminimal, if any, retooling or manufacturing changes being required ofthe food manufacturer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a self-contained temperature-changecontainer assembly that embodies the invention.

FIG. 2 is a top view of the container assembly of FIG. 1.

FIG. 3 is a side section view of the container assembly of FIGS. 1 and2.

FIG. 4 is a schematic diagram illustrating the manufacture oftemperature-change container assemblies in combination with theproduction of conventional packaged products.

FIG. 5 illustrates a safety feature useable with assemblies of the typedescribed in this document.

FIG. 5A is an enlarged view illustrating the safety feature of FIG. 5.

FIG. 6 is an enlarged view of another embodiment of a safety featuresimilar to the one of FIGS. 5 and 5A.

FIG. 7 depicts the attachment of an annular jacket top ring to acontainer in the manufacturing of the container assembly of FIGS. 1-3.

FIG. 8 illustrates the assembly of a jacket body around the jacket topring of FIG. 7.

FIG. 9 shows the filling of a steam condenser and a first reagentbetween the jacket body and the container of FIGS. 7 and 8.

FIG. 10 illustrates the installation of a reagent separator into thejacket body of FIGS. 7-9.

FIG. 11 depicts the placement of a second reagent into the jacket bodyof FIGS. 7-9.

FIG. 12 illustrates the installation of a jacket bottom onto the jacketbody of FIGS. 7-11.

FIG. 13 is a plan view showing the arrangement of penetrating spikes onthe jacket bottom of FIG. 12.

FIG. 14 is a side view showing the arrangement of the penetrating spikesof FIG. 13.

FIG. 15 illustrates a first layered configuration for the outer wall ofa container assembly that embodies the invention.

FIG. 16 shows a second layered configuration for the outer wall of acontainer assembly that embodies the invention.

FIG. 17 depicts a third layered configuration for the outer wall of acontainer assembly that embodies the invention.

FIG. 18 shows a jacket bottom member that forms a part of an alternativepreferred embodiment of the invention.

FIG. 19 shows a liquid reagent filled into the jacket bottom member ofFIG. 18.

FIG. 20 depicts a membrane applied to the jacket bottom member of FIG.18 over the liquid reagent shown in FIG. 19.

FIG. 21 illustrates the installation of a thin-profile jacket top ringaround the top of an inner container.

FIG. 22 shows the installation of a jacket body member to the jacket topring of FIG. 21.

FIG. 23 depicts the installation of a thermal insulator inside thejacket body member of FIG. 22.

FIG. 24 illustrates the placement of a steam condenser inside the jacketbody member shown in FIGS. 22 and 23.

FIG. 25 illustrates a second reagent filled inside the jacket bodymember of FIGS. 22-24.

FIG. 26 depicts the placement of a can support inside the jacket bodymember of FIGS. 22-25.

FIG. 27 shows the installation of the subassembly of FIGS. 18-20 to thesubassembly of FIGS. 21-26 to provide a self-contained assemblyembodying the invention.

FIG. 28 depicts an alternative construction in which a jacket bodymember and jacket top ring are formed integral with one another as asingle piece.

FIG. 29 is an enlarged detail view showing a region of top ring of FIG.28.

FIG. 30 is a side section view of an alternative activation assembly foruse with a self-contained temperature-change assembly according to theinvention.

FIG. 31 is a side section view of a fixture and a thin-walled plasticbag used in an alternative embodiment of the invention.

FIG. 32 is a side section view showing a steam condenser placed insidethe thin-walled plastic bag of FIG. 31.

FIG. 33 is a side section view showing a first reagent filed into thethin-walled plastic bag over the steam condenser shown in FIG. 32.

FIG. 34 is a side section view illustrating a step of vacuum sealing thethin-walled plastic bag of FIG. 33, with the first reagent and the steamcondenser sealed inside.

FIG. 35 shows a reagent subassembly constructed according to the stepsillustrated in FIGS. 31-34.

FIG. 36 shown the reagent subassembly of FIG. 35 placed inside an outerjacket subassembly.

FIG. 37 illustrates the installation of an activation subassembly ontothe outer jacket subassembly of FIG. 36.

FIG. 38 shows a plastic bag placed inside a fixture during the assemblyof an alternative embodiment of the invention.

FIG. 39 shows the filling of a solid first reagent inside the plasticbag of FIG. 38.

FIG. 40 shows a reagent subassembly created according to the stepsillustrated in FIGS. 38 and 39.

FIG. 41 illustrates an outer jacket subassembly with a steam condenserfilled inside it.

FIG. 42 shows the reagent subassembly of FIG. 40 installed in the outerjacket subassembly of FIG. 41.

FIG. 43 illustrates the installation of an activation subassembly ontothe outer jacket subassembly of FIG. 42 to complete an alternativeembodiment of the invention.

FIG. 44 is a side section view illustrating an embodiment of theinvention including a relatively broad, shallow inner container.

FIG. 45 is a side section view illustrating another embodiment of theinvention that features flared walls in a bowl-like configuration.

FIG. 46 shows an embodiment of the invention that includes a three-partouter jacket with two welds.

FIG. 47 illustrates another embodiment of the invention, with a two-partjacket and a single weld.

FIG. 48 illustrates an alternative activation mechanism for use withassemblies of the type described in this document.

FIG. 49 illustrates another embodiment, in which a user of the assemblycan place a product in the assembly's inner container prior toactivating the assembly to heat the product.

FIG. 50 illustrates an embodiment generally similar to that shown inFIG. 49, with an inner wall insulator applied to the inner wall of theassembly's inner container.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An exemplary embodiment of the invention is a self-containedtemperature-change container assembly that is assembled around astandard food can or a similar container that holds a food product oranother item that will be heated or cooled inside the container.

FIG. 1 is a perspective view illustrating a container assembly 3embodying the invention. The container assembly is assembled around aninner container 5—in this embodiment, a cylindrical metal can that holdsa quantity of a food or beverage.

The inner container 5 is partially enclosed inside an outer jacket 8,with the top 10 of the inner container exposed. A user can remove oropen the can's top using a pull-tab opener 12, a mechanical can opener(not shown), or other conventional means.

A visual indicator 15 is provided on the top 10 of the can 5 orelsewhere in a suitable location. This indicator's color or appearancechanges to signal that the can's top 10 (and by implication the food orbeverage inside) has reached a desired predetermined temperature, andthat the can's contents are thus ready to eat or drink. Before theassembly is activated, the visual indicator serves as a guard againsttampering and a confirmation that the container assembly 3 remainsundisturbed and ready for use.

A disposable utensil 17—which might be a drinking straw, a one-piece ortwo-piece plastic fork or spoon, or a combination spoon/fork (a“spork”)—can be attached by an adhesive or other similar means to theouter wall 20 of the jacket 8. This utensil can be packaged for securityand cleanliness inside a plastic or cellophane wrapper. A napkin or amoist disposable wipe (not shown) might be provided as well. The entireassembly can be shrink-wrapped or made to incorporate a tamper-evidentplastic lid.

The top 10 of the inner container 5 can be entirely removable from theassembly, as is usually the case with a canned soup or similar products.Means can also be provided for providing a small opening in the top sothat the contents of the container can be sipped or poured convenientlyand controllably without spilling.

FIG. 2 is a top view of the container assembly 3 illustrated in FIG. 1.The visual indicator 15 is an adhesive label pressed onto the top 10 ofthe inner container 5. The label is printed with a temperature sensitiveink that changes color (or otherwise provides a change in appearance) ata given predetermined temperature. When the container and its contentsare heated to this temperature, the ink changes color to show the userthat the contents of the can are ready for use. The color change is onetime only—the ink changes when the predetermined temperature is reached,but does not change back to its original color when the can cools backbelow its predetermined transition temperature. When the user looks atthe indicator and sees it in its original color or appearance, the usercan be confident that the assembly 3 has not been activated—whether byaccident or intentional tampering—and that the assembly thus remainsready for use. When the user activates the assembly, the user can watchthe indicator until it changes color, at which time the user will knowthat the food or beverage is hot and ready for use.

Other indicators may be used in place of the color-change labeldescribed here in connection with a preferred embodiment. An alternativevisual indicator might use a heat-sensitive ink that would becomevisible (or change from visible to invisible) at the predeterminedtemperature. Still other indicators might change their shape or someother condition to indicate to the products user that the product hadbeen activated at some time in the past or that the product is now readyfor use.

FIG. 3 is a side section view showing internal details of the containerassembly 3. The food, drink, or other contents 23 are held inside thesealed inner container 5. The inner container can be a custom containeror a conventional standard-sized can. The food, drink, or other contentscan, if desired, be placed inside the can as usual at a canning factoryand delivered to another location for assembly of the other elementsaround the can, or the food can be packaged and the entire assemblyassembled at one location. Preferred embodiments use standard cans,which is advantageous because it allows for a great variety of cannedfoods and drinks to be assembled into a self-heating assembly withoutany special tooling or manufacturing on the part of the foodmanufacturers. Voluntary can size standards are developed and published,for example, by the Can Manufacturers Institute Can Standards WorkingGroup.

A food producer may produce many individual cans of a product sealedinside standard size cans. Some of these units may be designated forconventional labeling and delivery for sale to consumers. Otheridentical units can be designated for incorporation in atemperature-change assembly of the type described here. Those assembliesmight be constructed at the canning facility or another location where afood or beverage is packaged inside the containers, or delivered toanother location for further assembly and later delivery for sale toconsumers. Use of standard containers in these assemblies means that nosignificant retooling or other manufacturing changes are required of afood producer in order to have their canned products incorporated inassemblies like those described in this document.

FIG. 4 illustrates schematically the manufacture of temperature-changecontainer assemblies according to the invention in combination with theproduction of conventional packaged products. Process step 150 indicatesthe packaging of products into closed containers. In a preferredembodiment, this step might represent the canning and sealing of a soupproduct or another food product inside standard metal cans or similarsealed metal containers.

Process step 152 represents the designation or diversion of the productsinside their containers into first and second portions. A first portion155 of the containers is sent for conventional labeling 158 and shipment160 for sale to consumers or other users. In preferred embodiments, cansof soup or another food product may be labeled in the usual way, andsent to markets and other points of sale for purchase and use byconsumers.

A second portion 163 of the containers is sent for further manufacturing165, in which the other elements of a self-contained temperature-changecontainer assembly according to the invention are assembled around thecontainers. The finished assemblies are then sent for shipment 167 forsale to consumers or other users. In a preferred embodiment,self-heating canned food products are placed on sale at markets andother points of sale for purchase and use by consumers.

Process step 152 may represent a physical process on a manufacturingline, or it may represent the mere designation of a certain portion ofthe packaged products for special handling. On a manufacturing line, forexample, a splitter may divide the line into two portions and selectsome cans for direct labeling and shipment, and others for furtherassembly into self-contained temperature change assemblies. Process step152 might also represent, for example, the manual designation anddivision of cans waiting for shipment inside a warehouse, where some ofthe cans are designated and labeled for sale as usual, and others aredesignated for inclusion inside assemblies of the type described in thisdocument.

A standard cylindrical food can 5 like that shown in FIG. 3 comprisesatop 10 and a bottom 25 with a cylindrical container wall 28 betweenthem. Conventional cans are usually steel, aluminum, or similarmaterials that are—conveniently for this invention—very effective heatconductors. The container's contents 23 can be a food, a drink, oranother item intended for use at a temperature above its usual storagetemperature.

The outer jacket 8 surrounds the inner can 5. The jacket in thisembodiment (for a cylindrical can) comprises an annular jacket top ring30, a cylindrical jacket body 32, and a jacket bottom 35. The jacketparts can be formed of an inexpensive ordinary plastic material. Thereis no direct contact between the plastic and the food 23 inside the can5 so special food-grade plastics are not required. The material thatforms the jacket parts should preferably have a relatively low thermalconductivity—lower in particular than the thermal conductivity of thematerial of the inner can 5.

A space is defined inside the jacket 8 between the inside of the jacketand the outside of the can 5. This space includes a first internalvolume 38 and a second internal volume 40, with an intermediary barrier42 between them.

The first internal volume 38 holds a first reagent 45, the secondinternal volume 40 holds a second reagent 50, and the barrier 42separates the two. In a preferred embodiment the first reagent isgranular calcium oxide and the second reagent is ordinary liquid water.The barrier can be a thin, breakable membrane such as a metal foil or aplastic film. Spikes or penetrators 53 are provided on the jacket bottom35, with the spikes pointing inward toward the barrier membrane reagentseparator 42.

To heat the contents 23 of the can 5, the user inverts the assembly 3 sothat it rests on the can's top 10 and the jacket top ring 30. The jacketbottom 35 is flexible enough so that the user can force the spikes 53through the membrane 42 by pressing down on the middle of the flexiblejacket bottom. When the user removes the pressure, the flexible jacketbottom returns to its original position, withdrawing the spikes andleaving several spaced-apart holes in the membrane. One such hole isproduced by each spike, and the holes are spaced-apart in a patterncorresponding to the spikes' configuration.

The liquid water second reagent 50 runs or drips out of the secondinternal volume 40 and into the calcium oxide first reagent 45 in thefirst internal volume 38. An exothermic reaction ensues as the waterpercolates downward through the granular calcium oxide. The heat of thisreaction is conducted preferentially through the bottom 25 and the wall28 of the can, which—being metal—conduct heat much better than theplastic of the outer jacket 8.

After a short time—after the liquid water second reagent 50 haspermeated sufficiently through the calcium oxide first reagent 40—theuser may flip the assembly 3 back into the upright configuration shownin FIG. 3. The reagent mixture will continue to produce heat and warmthe food for a considerable time until the reaction is complete. Duringthis time, convection currents (indicated by the arrows in FIG. 3) aregenerated in the food or drink 23, which helps to distribute the heatwithin the product so that the product is heated in a controlled mannerwith the food or drink brought to a relatively uniform temperaturethroughout the volume of the can 5.

In this embodiment, the penetrators are spaced apart from one anotherand configured so that each penetrator creates its own opening or holethrough the barrier film. This results in a spaced-apart pattern ofrelatively small holes. Such a pattern is advantageous in that the flowrate of the liquid water second reagent into the solid first reagent islimited by the limited area of the openings through the barrier. Thishelps to guard against a too vigorous reaction occurring at a localizedarea, as might be the case, for example, if the penetrators wereconfigured to tear through and create a large breach through thebarrier.

The configuration of this embodiment is also advantageous in that theholes created by the penetrators are generally smaller than the typicalgrain size of the calcium oxide first reagent. The barrier film can thussupport the weight of the calcium oxide and maintain the calcium oxidein close contact with the sides and bottom of the inner container, evenafter the barrier has been penetrated to mix the first and secondreagents and initiate the reaction. Such a configuration allows for moreefficient heating in comparison with other embodiments that create alarger breach through the intermediate barrier, and in which the solidreagent can thus fall through the breach and out of close contact withthe inner container.

The exothermic reaction between the calcium oxide 45 and the liquidwater 50 is a fairly strong one. Temperatures within the mixture canreach 400 degrees Fahrenheit (200 degrees Celsius) or more, and asignificant quantity of steam is generated.

A steam condenser 55 is provided in the first internal volume 38 aroundthe can 5 near the top of the jacket 8. In a preferred embodiment, thesteam condenser is a quantity of fairly loosely packed steel wool. Steelwool is an efficient conductor of heat, with a high surface arearelative to its volume. Hot steam that moves upward from the reagentmixture is cooled rapidly as it comes into contact with and condensesonto the steel wool. Significant heat is released, especially inchanging the steam from vapor to liquid water. This heat is transferredefficiently from the highly conductive steel wool into the also highlyconductive metal wall 28 of the can 5. The high surface area of thesteel wool provides a large effective surface area for condensation ofthe steam. The liquid water condensate is then available to drip backdown into the calcium oxide 45 to further the ongoing exothermicreaction. The reaction can continue for a considerable time, maintainingthe product at an appropriate temperature long after the initialheating.

The steam condenser might also be placed inside the second internalvolume, when the product is activated steam fills the entire interiorspace comprising the first and second internal volumes, so that a steamcondenser in the second internal volume might also be effective incondensing excess steam generated by the reaction.

FIG. 5 illustrates a further safety feature that may be included in someembodiments of assemblies of the type described in this document. Thisfigure illustrates the jacket bottom 35 that holds the penetrators 53and which contains liquid reagent 50 inside it. As with otherembodiments, pressing the jacket bottom inward urges the penetratorsthrough a barrier 42 which allows the liquid reagent to mix with a solidreagent inside the first internal volume 38.

This embodiment, though, includes an outlet 165 that vents steam in caseto prevent a condition of overpressure inside the assembly's jacket. Inthis embodiment, the outlet 165 is in the form of a normally closedhole, notch, or gap in the lower surface of the jacket bottom 35, incommunication with the first internal volume 38, which contains thefirst reagent, and in which the reaction and steam generation primarilyoccur.

The outlet 165 in this embodiment is normally closed by a relativelythin outlet barrier 168, which may simply be a thin plastic structureleft in place when the outlet is formed in the jacket bottom 35. (Theoutlet and outlet barrier can be seen best in the partial enlargement atthe bottom of FIG. 5A.) If the reaction occurs too quickly so thatexcess steam and high pressure are present inside the jacket, the outletbarrier ruptures to allow the overpressure to vent itself to the outsideof the jacket.

This embodiment includes a steam filter 170 inside the jacket betweenthe outlet 165 and the first internal volume 38. The steam filtercontrols the release of pressure and the passage of steam through theoutlet. Much or all of the steam that would otherwise pass through theoutlet will condense onto the steam filter, which enhances the safety ofthe device while still allowing release of excess pressure inside thejacket when required. The steam filter may be a small amount of ordinarycotton, felt, or some other porous or fibrous material that allows gasor vapor to pass through the outlet in a measured, controlled manner.The steam filter might also be some form of more elaborate mechanicalvalve constructed to allow venting of high pressure, although a simple,inexpensive material like cotton will usually be preferred for its lowcost, reliability, and ease of assembly.

FIG. 6 is an enlarged view that depicts another embodiment, in which theoutlet is in the form of a simple through-hole without a barrier betweenthe first internal volume 38 and the outside of the assembly. Such anembodiment is easy to make, and reliable, because its operation does notrely on the controlled rupture or opening of an outlet barrier inresponse to overpressure inside the jacket.

Although the outlet is shown in these figures as being formed throughthe jacket bottom, such outlets could be formed in the top or side ofthe jacket, or at any suitable location in communication with theinternal space in which the reaction takes place.

In some cases, it may be desirable to mix an inert material (one thatdoes not contribute to the temperature-change reaction) with the firstreagent 45 in the first internal volume 38. This can be done to moderatethe reaction to control the rate of the reaction and the rate and amountof heat generation.

The reaction rate may also be moderated by providing a second quantityof the liquid reagent inside the first internal volume inside a plasticbag with an appropriate melting point. When the liquid reagent mixeswith the solid reagent, the temperature will rise inside the jacketbody. At some point, the temperature will exceed the melting point ofthe bag that contains the second quantity of the liquid reagent, whichwill then be released into the first reagent to contribute further tothe reaction.

If desired, an appropriate substance may be added to the liquid reagentto lower its freezing point to protect the liquid reagent againstfreezing as the assembly is transported or stored. Common sodiumchloride salt is an inexpensive substance that can lower the freezingtemperature of liquid water substantially.

A variety of different reagent combinations might be used in differentembodiments. The first reagent may be a combination of an acidicanhydride or salt and a basic anhydrade or salt. Adding water as asecond reagent to such a first reagent mixture will produce heat and anacid/base mixture. The neutralization reaction between the acid and thebase produces additional heat, and a safe, neutral, easily disposableend product.

Possible reagent mixtures include calcium oxide (CaO) in combinationwith phosphorous pentoxide (P₂O₅); calcium oxide in combination withaluminum chloride (AlCl₃), calcium oxide in combination with oxalic acid(H₂C₂O₄), and calcium oxide in combination with magnesium chloride(MgCl₂). Other reagent mixes are possible as well, and an inert materialmight be added to such a first reagent mix, if desired, to control therate and degree of heat produced in the reaction. Mixture proportionsmight include, for example, between 100-125 grams of calcium oxide,between 0-30 grams of oxalic acid, and between 0-15 grams of inertmineral oil.

A “two-stage” reagent mix can be achieved by using an inert material incombination with less than the entire amount of one of the reagents.Such a mix might include, for example, calcium oxide, a portion of whichis coated with an inert mineral oil, and a portion of which is uncoated.

When water enters such a mixture, the uncoated portion is quicklyexposed to the water and begins producing heat rapidly and immediatelythrough the resulting exothermic reaction. The coated portion isinitially shielded from contact with the water, and does not at firstcontribute much to the reaction.

As the reaction continues, though, the mineral oil coating begins tobreak down and be penetrated by the water. As this happens, more andmore of the coated portion of the calcium oxide begins contributing tothe reaction, effectively replacing to some extent the calcium oxideconsumed previously in the reaction. Such a “two-stage” mixture thusprovides quick initiation of heat generation from the reaction(primarily from initially contact between the water and the uncoatedportion of the calcium oxide), followed by a longer, sustained heatgeneration as more and more of the coated portion begins contributing tothe overall reaction.

The goal, of course, is to devise a reagent mix that combines quickinitiation and rapid heating of the food product, followed by asustained heat generation that will keep the food inside the innercontainer warm for a considerable time, all while economizing on theamounts of reagents used and seeking to avoid a too vigorous reactionthat might, for example, create an overpressure inside the reagentcontainer or scorch or burn the food inside the inner container.

Any of a considerable variety of reagent mixes might be found optimalfor a particular application. Generally speaking, a two-stage reagentmix might have only 15-90% of its calcium oxide (by weight) coated withmineral oil as an inert material. The weight of the mineral oil used inthe coated portion might be between 1% and 20% of the total weight ofthe calcium oxide (the coated and non-coated portions, weighed beforeany is coated) used in the overall mix.

In one particular reagent mix used in a presently preferred embodiment,the calcium oxide is divided into two portions −70% by weight is coatedwith mineral oil and 30% is not. The weight of the mineral oil used tocoat the coated portion in this embodiment is 7% of the weight of thatportion of the calcium oxide to be used in the coated portion (weighedbefore coating). A mix of this composition might thus include 100 gramsof calcium oxide, with 70 grams of that being coated with about 5 gramsof mineral oil, and the two portions then being mixed back together as acombined first reagent for use in combination with water as a secondreagent.

Although the preferred embodiment described here is intended primarilyfor heating a food or beverage, other applications are alsocontemplated. There are, for example, certain cosmetic, medical,pharmaceutical, therapeutic, or sports appliances—bandages, wraps,treatments for soreness or stiffness, and the like—that are intended tobe applied to a user's body at temperatures above room temperature. Suchproducts could be enclosed inside a container in an assembly like thatdescribed here, for activation and application at the desired elevatedtemperatures, even at locations where more conventional heatingequipment is not available. Food products can include foods andbeverages, in single servings or multiple-portions, includingplatoon-size meals for military or similar use in the field. Foods mayobviously include entrees, side dishes, baby foods or formulas, petfoods, or any other food or beverage for which heating or cooling mightbe desired.

Moreover, although such an assembly will commonly be used to heat aproduct from room temperature to well above room temperature, the use ofthe invention is not so limited. Some products may best be stored, evenin a sealed container, in a refrigerator or freezer at a temperaturewell below room temperature. In that case, an assembly of this typemight be used to quickly bring the product up to room temperature foruse, or in any event up to a temperature above the product's normalstorage temperature.

Finally, although the invention is embodied here in a self-heatingassembly that uses an exothermic reaction to deliver heat to theproduct, other reagents could be used that would, upon mixing, initiatean endothermic reaction to extract heat from the container and therebycool a product contained inside it. Cold beer or wine, water, juices, orsoft drinks could be delivered at locations away from conventionalrefrigeration and without the need for heavy and space-consuming ice orfreezer appliances. There are also sports wraps and similartherapies—such as those intended to treat minor sprains and reduceswelling—that are best applied at temperatures well below normaltemperature. These products and others—including but by no means limitedto food entrees and side dishes including baby food or formulas, andbeverages such as beer, wine, coffee, tea, cocoa, or hot apple cider,and non-food products including hair dyes, hot oil hair treatments,self-heating beauty wax treatments, surgical tools, and otherproducts—might be delivered for convenient use inside a self-containedtemperature-change container according to the invention.

FIGS. 4-9 illustrate process steps in the manufacturing of a containerassembly that embodies the invention. FIG. 4 illustrates the attachmentof the annular jacket top ring 30 around the edge of the top 10 of theinner container metal can 5. The top ring is placed generally flush withthe top edge of the can, and secured to the can by an adhesive or by anyother suitable method. If desired, the food, drink or other contents canbe put into the can and the can sealed at an ordinary canning facility,which may be at a location other than that at which the finished productis assembled. Standard sealed cans identical to those usually sold toconsumers can be delivered to the assembly location for inclusion in thefinal product.

FIG. 5 illustrates the attachment of the outer jacket body 32 to the topring 30. After the top ring is fixed at the top 10 of the can 5, the canand the top ring are turned top down so that the outer jacket body canbe fixed around the top ring. The jacket body can be secured to the topring by any suitable method, including adhesive fixing, or heat, sonic,or spin welding.

FIG. 6 depicts a filling of the steel wool 55 and the calcium oxide 45(in that order) into the interior of the jacket body 32 around theoutside of the can 5. The calcium oxide is filled as shown in FIG. 6 toa depth sufficient to cover the inverted body 25 of the can.

FIG. 7 shows the attachment of the aluminum metal foil or plastic filmmembrane 42 over the top of the calcium oxide first reagent 45. As thepartial enlargement portion of FIG. 7 illustrates, the inner wall of thejacket body 32 has a stepped profile at the location where the membrane42 is to be anchored. The calcium oxide is filed into the jacket body toa height near the step 57, so that the membrane is installed close tothe calcium oxide reagent. The membrane can be attached to the innerjacket body wall by any suitable method, including thermal or presswelding.

After the membrane barrier 42 is in place over the calcium oxide firstreagent 45, the liquid water second reagent 50 is placed into the jacketbody 32 over the membrane, as FIG. 8 indicates.

FIG. 9 depicts the installation of the jacket bottom 35 inside thejacket body 32. The jacket bottom is positioned so that the spikes 53 donot pierce the membrane 42, but close enough so that they will piercethe membrane when the user presses the jacket bottom inward toward themembrane. The jacket bottom can be fixed to the jacket body by anysuitable method, including adhesive fixation, or thermal-, sonic-, orspin-welding.

Fixation of the jacket bottom 35 to the jacket body 32 completes thisstage of the assembly. Further steps may involve applying labels to thejacket body. If desired, one or more insulating layers can be appliedbetween the jacket body and an outer layer, to further inhibit transferof heat to the outside of the assembly.

Several characteristics are desired for a self-heating assembly of thetype described above. First, it is desirable that the quantity of heatgenerated in the exothermic reaction be sufficient to heat the food tothe desired temperature, and to hold the food at an appropriatetemperature for an appreciable period of time. Second, the reactionshould be vigorous enough to heat the food quickly to the desiredtemperature, so that the user does not have to wait too long between hisactivation of the assembly and the time when the food is heated andready for consumption. Third, it is vital that the product be safe.There should be no danger of any overpressure that might rupture thejacket; nor should the outer surfaces of the jacket become too hot totouch or for the user to hold comfortably in his or her bare hands.Finally, the product should not be prone to accidental activation, andthe user should be assured that no such premature activation hasoccurred. The preferred embodiment described above includes severalfeatures that contribute to the achievement of these goals.

FIG. 10 is a plan view illustrating a configuration of the spikes ormembrane penetrators 53 on the jacket bottom 35. FIG. 11 is acorresponding side section view of the spikes on the jacket body, and alower portion of the jacket body 32. Multiple spikes are arrayed acrossthe surface of the jacket bottom. In this embodiment, nine spikes coversubstantially the entire surface of the jacket bottom, oppositesubstantially the entire surface of the membrane.

When the jacket bottom 35 is flexed toward the membrane, the spikes 53form a pattern of relatively small holes distributed over thesubstantially the entire area of the membrane, one hole at the locationof each spike. This allows the liquid water first reagent to drip in acontrolled way into the calcium oxide second reagent. The water flow isdistributed across the surface of the calcium oxide rather thanlocalized at a single point, and the water drips onto the calcium oxidethrough multiple small holes rather than simply flooding into it througha single, large rupture in the membrane. This allows the reaction toproceed fairly rapidly while avoiding local overheating or overpressureat any single place within the calcium oxide reagent. It will generallybe desirable to provide at least three spaced-apart spikes to penetratethe membrane, and five or more spikes will often be preferred.

The steel wool steam condenser 55 at the top of the volume 38 thatcontains the calcium oxide 45 helps to moderate overproduction of steamin the reaction. Steam generated in the reaction can condenseefficiently on the large surface area of the steel wool filaments. Heatreleased by this condensation is transmitted efficiently from the highlyconductive steel wool into the (also highly conductive) outer surface ofthe metal can 5.

To heat the food efficiently while maintaining the outside of theassembly 3 at a comfortable temperature, it is desirable that the heatgenerated in the reaction be transmitted highly preferentially into thecan 5, rather than through the material of the jacket 8 to the outsideof the assembly. This is achieved to a significant extent due to thedifferent thermal conductivities of the different materials. The metalof the can conducts heat much more readily than either the plastic ofthe jacket or any thermal insulator that might be used between thejacket and the steel wool.

If desired, heat flow to the exterior of the assembly 3 can be furtherlimited by applying appropriate insulators to the interior or exteriorof the plastic jacket 8, or within the material of the jacket itself.FIG. 15 shows one such application. In this embodiment, a firstinsulator paper layer 60 is applied to the inner side of the jacket body32, between the calcium oxide and the jacket body. In this embodiment,moreover, air pockets 61 are present between multiple layers thatjointly comprise the jacket body. These air pockets are maintained byribs, corrugations, or similar structure (not shown) between themultiple layers of the jacket body. The internal paper layer provides afirst degree of insulation, and closed pockets of trapped air such asthose within the jacket body are highly effective insulators.

The inner insulator layer 60 shown in FIG. 15 could also comprise ametallic foil such as an aluminum foil between the first reagent 45 andthe plastic outer jacket body material 20. Such a foil would protect theplastic from heat to prevent its melting under the heat of theexothermic reaction.

Another configuration of layered insulators is shown in FIG. 16. Thisembodiment includes an inner layer 63 of molded or pressed fiber such asthat commonly used in pressed egg containers. This inner layer isapplied to the inside of the jacket body 32. A thin (3 millimeter) layer65 of expanded polystyrene foam (e.g., Styrofoam®) is applied over thejacket body. The Styrofoam® layer is an effective insulator with asurface that is easily and comfortably gripped and held by a user of theproduct. The Styrofoam® layer is also appropriate for the printing ofpermanent, colorful, and attractive visual designs, and is thuswell-suited for use as the product's identifying label.

Still another layered configuration is shown in FIG. 17. This embodimentincludes a molded or pressed fiber layer 63 applied to the inside of thejacket body 32 as in the prior configuration, and a Styrofoam® layer 65applied to the outside of the assembly. This embodiment includes anadditional layer of corrugated cardboard 67 between the plastic of thejacket body and the Styrofoam®. The corrugated cardboard defineschannels or voids in which air pockets are held—and these air pocketsare of course highly effective insulators.

Particular embodiments may use alternate insulation materials. Inparticular, a sprayable foam or ceramic insulator can be used in placeof or in addition to any of the insulative layers described in thisdocument. Such materials can be applied by spraying through multi-headnozzles and are thus suitable in high speed industrial production. In apreferred embodiment, a multiple layer outer jacket 20 (see FIG. 15) isproduced by, e.g., injection molding or blow molding to produce an outerjacket with ribs or corrugations separating the individual layers andair spaces 61 trapped between them. A sprayable foam or ceramic layer 60is then applied to the inner surface of the outer jacket.

An alternative preferred construction is illustrated in FIGS. 18-24.FIG. 18 shows a cup-shaped jacket bottom member 35 that carries a numberof pointed penetrators or spikes 53. Water or another liquid reagent 50is filled into the internal volume 40 in the bottom member'supward-facing cup as shown in FIG. 19. The film or foil membrane barrier42 is then fastened over the spikes and the internal volume as shown inFIG. 20 to hold the liquid reagent inside the cup. The membrane issecured to the bottom member by an adhesive, heat-sealing, ultrasonicwelding or any other suitable means. Sealing the membrane over theliquid reagent packages the reagent inside a self-contained activationsubassembly 80.

FIG. 21 illustrates the installation of a thin-profile jacket top ring30 around the top 10 of the inner container 5. The top ring is slippedfrom the bottom of the can upward into engagement with the lower edge ofthe rim 83 near the top of the can. The normal, unstressed innerdiameter of this top ring is slightly less than the outer diameter ofthe can. A watertight, airtight seal is thus formed between the top ringand the can wall 28 when the ring is slipped onto the can.

As the detail view in FIG. 21 illustrates, this top ring 30 includes anotch 85 around the upper surface of the top ring. FIG. 22 shows theinstallation of a jacket body member 32 to the top ring. This jacketbody member includes a notch engaging ring, configured to engage withthe top ring's notch, and a can rim engaging ring 90, configured toengage the inside of the rim 83 at the top of the can 5. The jacket bodymember is fixed to the top ring by ultrasonic welding, spin welding, orany other suitable method.

After the jacket body member 32 is fixed to the top ring 30, theresulting can/jacket body subassembly is inverted as shown in FIG. 23. Athermal insulator 92 is then placed inside the internal volume 38between the can 5 and the jacket body member 32, near the inner wall ofthe jacket body member. The thermal insulator can be a corrugatedcardboard or pressed paper material, a reflective foil, a reflectivepaint applied to the jacket body's inner wall, or any other suitablethermal insulator.

FIG. 24 illustrates the placement of the steel wool steam condenser 55inside the internal volume 38 around the top 10 (shown inverted in thisfigure) of the can 5. As FIG. 25 shows, calcium oxide 50 or anothersuitable reagent is then filled into the internal volume over the steamcondenser to a depth that covers the inverted bottom 25 of the can.

Then, as indicated in FIG. 26, a can support 95 can be placed inside thejacket body member 32 to support the can. The can support includes a lip98, which engages with the bottom 25 of the can 5, a can support base100, and a support column 95 to support the lip over the base. The exactconfiguration of the can support can vary considerably. It may includemultiple support columns, for example, and the base can be a simple,thin bar, a circular member running around the circumference of theouter jacket, or any other suitable shape so long as sufficient openspace is left to allow the liquid reagent to drip down into the firstreagent inside the jacket body member. The can support is in factoptional, and may not be included at all in some preferred embodiments.

The assembly is completed as illustrated in FIG. 27 by installing theactivation subassembly 80—comprising the flexible bottom member 35, thebarrier membrane 42, and the liquid water second reagent 50- to thebottom of the jacket body member 38 to seal the calcium oxide firstreagent 45 inside the jacket. Additional insulation layers or productpackaging can be applied over the outside of the jacket body if desired.This is assembly is used in the same way as the previous one, by flexingthe jacket bottom to force the spikes 53 through the barrier. Thisleaves a pattern of holes through the barrier—one hole corresponding toeach penetrator, and the liquid second reagent 50 can then move throughthe holes and into contact with the first reagent 45 to initiate thetemperature change reaction.

FIGS. 28 and 29 illustrate yet another preferred embodiment. FIG. 28shows a jacket configuration in which the jacket body 32 is formedintegral with the jacket top ring 30, rather than as separate piecesjoined together as in the previous figures. FIG. 29 is a detail viewshowing the region where the top ring of the integral jacket embodimentcontacts the upper edge of the can 5.

In this embodiment, as in the previous one, the jacket top ring 30 isslipped over the outside of the can 5. Referring particularly to thedetail view of FIG. 29, the top ring includes lower seal retainer 105and an upper seal retainer 107. A seal 110 is retained in contact withthe side of the can between these two seal retainers. The seal may be anelastomeric or otherwise flexible O-ring, a hardening liquid seal suchas a hot liquid glue or a liquid elastomer that hardens upon cooling, orany other suitable material. The rim 83 of the can is gripped betweenthe upper seal retainer 105 and an upper can rim retainer 113. Thisembodiment and its assembly are otherwise generally similar to the otherembodiments described previously. The reagents, principles of operation,and applications are generally the same.

FIG. 30 is a side section view of an alternative actuator 115 for use intemperature-change assemblies of the type described here. This actuator,like those described above, can be incorporated as a jacket bottom 35 ina jacket assembly surrounding an inner container. As in the other jacketbottoms, this one includes several spikes, or penetrators 53 on amovable member disposed opposite a foil, film, or other membrane-likebarrier. Each of the spikes in this embodiment includes two penetratingspike tips 117 with a notch 120 between them. The spike tips penetrateand tear the membrane. The notches provide open flow paths through theresulting holes for the liquid second reagent to flow through themembrane into contact with the solid first reagent.

The embodiment of FIG. 30 differs slightly from the embodimentsdescribed above. This embodiment includes a flexible “hinge” 123 aroundthe rim of the jacket bottom 35. To operate an assembly that includesthis actuator 115, the user presses the jacket bottom on the sideopposite the spikes 53. The hinged rim 123 is flexible enough to allowthe spike tips 117 through the membrane. In this case, though, when thejacket bottom has moved on the hinge, it does not move back into theoriginal configuration shown in the drawing when the pressure isremoved. The jacket bottom, in other words, does not flip back outwardacross the rim hinge. This provides the user with a way of knowingwhether or not a given assembly has been activated previously. If thehinge rim is flipped inward, the jacket bottom has been pressed. If not,the assembly remains ready for use.

This embodiment further includes an outer rim surface 125, whichprovides a convenient location for anchoring a membrane to the actuator115, or for securing the actuator to other elements of the overallassembly.

Reagents used in prior temperature-change assemblies have been subjectto degradation over time. Calcium oxide, for example, is veryhygroscopic and its absorption of water from the atmosphere might limitthe shelf life of the product. In the embodiments described below, thesolid first reagent is packaged inside a vacuum-sealed plastic baghaving a virtually zero water vapor transmission rate.

FIG. 31 illustrates a fixture 128 for filling the first reagent into anopen plastic bag 130. The fixture includes a cylindrical central support132 of a size corresponding at least generally to the size of the innercontainer of the final assembly. The fixture also includes an outer wall135 around the central support; the outer wall is sized to correspond tothe size of the outer jacket in the final assembly. An open bag isplaced inside the outer wall and over the central support as shown inFIG. 31.

The steel wool steam condenser 55 is then filled into the plastic bag130 to a desired depth appropriate for the final assembly, asillustrated in FIG. 32. The first reagent is filled into the bag overthe steam condenser, as shown in FIG. 33. The open top of the bag isthen vacuum-sealed as shown in FIG. 34. Sealing the bag provides acompletely vapor tight reagent subassembly 137, which is shown removedfrom the support figure in FIG. 35.

FIG. 36 illustrates the placement of the filled solid reagentsubassembly 137 (carrying the steam condenser 55) into an insulatedouter jacket subassembly 140. The outer jacket subassembly and itsconstruction may be substantially identical to that of the assemblydescribed above in connection with FIGS. 21-23. The solid reagentsubassembly is slipped into the outer jacket body 32 between a layer ofthermal insulation 92 and the outer wall 28 of the filled innercontainer 5.

The assembly is completed, as shown in FIG. 37, by installing awater-filled activation subassembly 80 to close the bottom of the outerjacket. The activation subassembly may be configured and assembled insubstantially the same way as that described above in connection withFIGS. 18-20, or it may use the alternate actuator described above inconnection with FIG. 30.

The solid first reagent 45 is thus packaged inside a vapor-barrier inthe form of the thin-walled plastic bag 130. The material of the bagshould be thin (perhaps on the order of 1-2 one-thousandths of an inch(0.004-0.008 millimeters)), and may advantageously be of a plastic witha low melting temperature. When the activation device 80 is depressed,its spikes 53 penetrate the foil or plastic membrane 42 to release theliquid second reagent 50. The spikes then penetrate further through thebag 130 to allow the liquid reagent to reach the solid reagent 45 insidethe bag. This initiates the exothermic reaction in a relativelycontrolled way as the liquid percolates into the solid reagent throughthe openings in the membrane and the holes in the bag. As thetemperature rises, the low melting temperature bag material melts away,thereby allowing more and more of the liquid to reach the solid reagent.The reaction accelerates, but without the initial steep temperaturespike that might occur if the liquid reagent were simply dumped all atonce into the solid.

The bag configuration 130 shown in these figures is also advantageous incorresponding generally to the space between the jacket body 32 and theinner container 5. If the solid reagent 45 is packed reasonably tightinside the bag, the solid reagent and the bag can provide structuralsupport for the inner container inside the jacket. This may allow forthe omission of the can support 95 (see FIG. 24), and the elimination ofthe assembly step required to place such a can support inside thejacket.

Still another configuration is illustrated in FIGS. 38-43. This variantpackages the first reagent 45 inside a plastic bag 130 as before, butthe steam condenser in this variant is outside the bag. FIG. 38 showsthe placement of the open plastic bag inside a supporting fixture 128.FIG. 39 illustrates the filling of the first reagent 45 into the bag.After the bag is filled and vacuum-sealed, it is lifted off the fixtureas shown in FIG. 40. The steam condenser 55 is provided inside the outerjacket subassembly 140 as shown in FIG. 41 (and not inside the bag, asin the previous embodiment). The reagent filled bag 130 is then placedaround the inner container 5 and over the steam condenser 55 inside theouter jacket body 32 as shown in FIG. 42. Finally, the activationsubassembly 80 carrying the liquid reagent 50 is then sealed over theopen end of the jacket body as shown in FIG. 43.

Other possible configurations are illustrated in FIGS. 44-47. FIG. 44 isa side-section view illustrating a configuration in which the innercontainer 5 is a can that is relatively shallow in compared to the canshown, e.g., in FIGS. 1-3.

FIG. 45 depicts an embodiment in which the inner container 5 and theouter jacket 8 each have sides that flare outward and upward in abowl-like configuration that can be held securely and conveniently by auser consuming the product. The embodiment shown in FIG. 45 alsofeatures vent outlets 165 and steam filters 170 of the type describedabove in connection with FIG. 3A.

FIG. 46 illustrates an embodiment that features a three-piece outerjacket 8 that includes two spin weld joints. This embodiment isassembled by first snapping an annular top ring 30 over the top rim ofthe inner container 5. A jacket body member 32 is then spin welded tothe top ring at a first spin weld site 173. A lower activationsubassembly 80 is then spin welded to the jacket body member 32 at asecond spin weld site 175. If desired, the order in which the spin weldsare formed could be changed, or alternative weld-forming methods couldbe used instead of spin welding as described here.

FIG. 47 shows another embodiment the features a relatively long top ring30 that extends downward to the lower activation subassembly 80. Thisembodiment requires only a single spin weld, at a first spin weld site173.

FIG. 48 depicts an alternative activation device 178. In thisconfiguration, several penetrators 53 fixed to a mounting structure inthe form of a central shaft 180. The device includes a flexible memberin the form of a pushbutton 183 formed, for example, of a relativelysoft polymeric material that is substantially more flexible than therelatively rigid material of the outer jacket that surrounds the innercontainer. When a user presses the pushbutton, the central shaft 180 isurged upward (relative to the figure), which in turn forces thepenetrators 53 upward and through the barrier.

FIG. 49 is a side-section view of an alternative embodiment that can beshipped and sold with the inner container 5 empty. This embodimentincludes a removable and replaceable lid 185. The removable lid may be arelatively thin and somewhat flexible plastic, for example, with a ridgeor lip 187 that fits into place over a rim 190 around the outside of theupper edge of the wall 28 of the inner container 5.

To use this assembly, the user removes the lid 185 from the innercontainer 5. The user can then place his own food or another item orsubstance that he would like to have heated inside the inner container.The user then replaces the lid onto the inner container, and activatesthe assembly in the same way as the assemblies described above. Thereaction between the solid first reagent 45 and the liquid secondreagent 50 generates heat, which is transferred through the walls of theinner container and into user's own product.

The lid 185 includes a vent 193 in the form of an opening or holethrough the lid, in this case in the lid's center. This vent allowspressure to escape from the inner container 5 as the product is heated.A steam filter 195, which may be felt or another porous or permeablematerial, covers the vent 193 to prevent or moderate the ejection of hotsteam from the container.

FIG. 50 depicts another embodiment generally similar to that of FIG. 49.This embodiment, though, includes an inner wall insulator 197. The innerwall insulator may be a, e.g., a layer of cardboard, plastic, or a layerof plastic over a layer of cardboard. The inner wall insulator mightalso be in the form of a plastic cup or the like inserted into the innercontainer. The inner wall insulator should be configured to allow heatto flow fairly readily from the wall of the inner container into thesubstance placed into it, but the inner wall insulator should providejust enough thermal insulation so that a user will not burn himself, forexample, if he activates the product and places his hand inside theinner container 5 in contact with its inner wall 28. The inner wallinsulator should thus be in fairly close contact with the innercontainer, and selected and dimensioned to provide only the necessarydegree of thermal insulation.

Though it is generally contemplated that all parts of the assembliesdescribed in this document will be disposable, for convenience, at leastparts of the assembly could be re-used and recycled by refilling theassembly with new temperature change chemicals and reinstalling anewly-filled inner container into the assembly.

Several self-contained temperature-change assemblies have been describedto as examples of how the invention might be configured. The inventionis not limited to these exemplary assemblies, though, and variousmodifications or additions will no doubt occur to those of skill in theart. The true scope of the invention should thus be determined primarilyby reference to the appended claims, along with the full scope ofequivalents to which those claims are legally entitled.

1. A self-contained, temperature-change container assembly comprising:an inner container; an outer jacket at least partially surrounding theinner container, wherein a first internal volume and a second internalvolume are defined between the inner container and the outer jacket; afirst temperature-change reagent inside the first internal volume; asecond temperature-change reagent inside the second internal volume; areagent separator between the first internal volume and the secondinternal volume; and a movable member situated opposite the reagentseparator, wherein movement of the movable member opens the reagentseparator to allow mixing of the first and second temperature-changereagents in a reagent mixing region inside the outer jacket; wherein thefirst temperature-change reagent includes a solid material, and thesecond temperature-change reagent includes liquid water; and wherein thefirst-temperature change reagent includes a first portion that is atleast partially covered by a non-water soluble inert material thatinhibits a chemical reaction between the first and second temperaturechange reagents, and a second portion that is not at least partiallycovered by the inert material, and wherein the first and second portionsare intermixed with one another inside the first internal volume.
 2. Theassembly of claim 1, wherein the first temperature-change reagentincludes calcium oxide and the inert material includes mineral oil. 3.The assembly of claim 1, wherein the weight of the first portion of thefirst temperature-change reagent is between 15% and 90% of the totalweight of the first temperature-change reagent, each said weightmeasured exclusive of the weight of the inert material.
 4. The assemblyof claim 1, wherein the weight of inert material used with the firstportion of the first temperature-change reagent is between 1% and 20% ofthe total weight of the first and second portions of the firsttemperature-change material measured exclusive of the weight of theinert material.
 5. A reagent combination for use in a self-containedtemperature change container assembly, the combination comprising: asolid first temperature change reagent; and liquid water as a secondtemperature change reagent; wherein the first temperature change reagentincludes a first portion that is at least partially covered by anon-water soluble inert material that inhibits a chemical reactionbetween the first and second temperature change reagents, and a secondportion that is not at least partially covered by the inert material,wherein the first and second portions are intermixed with one another.6. The reagent combination of claim 5, wherein the firsttemperature-change reagent includes calcium oxide and the inert materialincludes mineral oil.
 7. The reagent combination of claim 5, wherein theweight of the first portion of the first temperature-change reagent isbetween 15% and 90% of the total weight of the first temperature-changereagent, each said weight measured exclusive of the weight of the inertmaterial.
 8. The reagent combination of claim 5, wherein the weight ofinert material used with the first portion of the firsttemperature-change reagent is between 1% and 20% of the total weight ofthe first and second portions of the first temperature-change materialmeasured exclusive of the weight of the inert material.